Intellectual Ventures has launched an effort to design nuclear energy reactors that improve on those in operation today. Known as TerraPower, the project has produced preliminary designs for a new class of nuclear reactor, called a Traveling-Wave Reactor (TWR). The TWR can run for 50 to 100 years without refueling or removing any used fuel from the reactor. By greatly simplifying the nuclear fuel cycle, TWRs could improve the cost, safety, social acceptability, and long-term sustainability of nuclear energy as a source of emissions-free electricity.

The Science

Nuclear power plants produce electricity from the heat generated when big and unstable atoms, such as plutonium and the rare form of uraniumcalled U-235, split apart into smaller atoms. Each time a big atom splits (or “fissions”), it releases fast-moving neutrons and other subatomic
particles that leads to a chain reaction. A nuclear reactor produces and controls the release of energy from splitting atoms of certain elements. Nuclear electricity plants today use fuel made from natural uranium that has been enriched. The TWR, in contrast, initially contains only a small igniter of fissile fuel, which is used to kick off the chain reaction. The wave of fission would move slowly through the core, splitting many more of the fuel atoms than a conventional reactor would.A TWR reactor core would be filled with fuel that is made out of atoms that are big but not unstable enough to cause a chain reaction on their own. The fuel could be depleted uranium, for example, which is the common U-238 form of the element that is currently set aside as waste when U-235 is taken out of natural uranium at enrichment plants.

A Simpler, Safer Fuel Cycle

Unlike light water reactors, the TWR can theoretically run forever without ever needing any additional enriched uranium after its startup period. This fleet could supply the world’s needs for energy for thousands of years without any need for chemical reprocessing of the used fuel. This ability is a major advance in reducing the inherent risks of weapons material proliferation.

Many Shapes and Sizes

TerraPower’s scientists and engineers are investigating a wide range of designs for TWRs. Small, modular units that generate 100 megawatts of electricity may be feasible and could fit the needs of emerging markets. Conceptual designs for gigawatt-scale reactors, big enough to power a city and similar in outward appearance to existing plants, are well underway. And TerraPower is studying and simulating many other varieties. At Intellectual Ventures, the process of invention continues every day.

TR10: Traveling-Wave Reactor
A new reactor design could make nuclear power safer and cheaper, says John Gilleland.

Enriching the uranium for reactor fuel and opening the reactor periodically to refuel it are among the most cumbersome and expensive steps in running a nuclear plant. And after spent fuel is removed from the reactor, reprocessing it to recover usable materials has the same drawbacks, plus two more: the risks of nuclear-weapons proliferation and environmental pollution.

These problems are mostly accepted as a given, but not by a group of researcher s at Intellectual Ventures, an invention and investment company in Bellevue, WA. The scientists there have come up with a preliminary design for a reactor that requires only a small amount of enriched fuel--that is, the kind whose atoms can easily be split in a chain reaction. It's called a traveling -wave reactor. And while government researchers intermittently bring out new reactor designs, the traveling-wave reactor is noteworthy for having come from something that barely exists in the nuclear industry: a privately funded research company.

As it runs, the core in a traveling- wave reactor gradually converts nonfissile material into the fuel it needs. Nuclear reactors based on such designs "theoretically could run for a couple of hundred years" without refueling, says John G illeland, manager of nuclear programs at Intellectual Ventures.

Gilleland's aim is to run a nuclear reactor on what is now waste. Conventional reactors use uranium-235, which splits easily to carry on a chain reaction but is scarce and expensive; it must be separated from the more common, nonfissile uranium-238 in special enrichment plants. Every 18 to 24 months, the reactor must be opened, hundreds of fuel bundles removed, hundreds added, and the remainder reshuffled to supply all the fissile uranium needed for the next run. This raises proliferation concerns, since an enrichment plant designed to make low-enriched uranium for a power reactor differs trivially from one that makes highly enriched material for a bomb.

But the traveling-wave reactor needs only a thin layer of enriched U-235. Most of the core is U-238, millions of pounds of which are stockpiled around the world as leftovers from natural uranium after the U-235 has been scavenged. The design provides "the simplest possible fuel cycle," says Charles W. Forsberg, executive director of the Nuclear Fuel Cycle Project at MIT, "and it requires only one uranium enrichment plant per planet."

The trick is that the reactor itself will convert the uranium-238 into a usable fuel, plutonium-239. Conventional reactors also produce P-239, but using it requires removing the spent fuel, chopping it up, and chemically extracting the plutonium--a dirty, expensive process that is also a major step toward building an atomic bomb. The traveling-wave reactor produces plutonium and uses it at once, eliminating the possibility of its being diverted for weapons. An active region less than a meter thick moves along the reactor core, breeding new plutonium in front of it.

The traveling-wave idea dates to the early 1990s. However, Gilleland's team is the first to develop a practical design. Intellectual Ventures has patented the technology; the company says it is in licensing discussions with reactor manufacturers but won't name them. Although there are still some basic design issues to be worked out--for instance, precise models of how the reactor would behave under accident conditions--Gilleland thinks a commercial unit could be running by the early 2020s.

While Intellectual Ventures has caught the attention of academics, the commercial industry--hoping to stimulate interest in an energy source that doesn't contribute to global warming--is focused on selling its first reactors in the U.S. in 30 years. The designs it's proposing, however, are essentially updates on the models operating today. Intellectual Ventures thinks that the traveling-wave design will have more appeal a bit further down the road, when a nuclear renaissance is fully under way and fuel supplies look tight.

"We need a little excitement in the nuclear field," says Forsber g. "We have too many people working on 1/10th of 1 percent change."

Nuclear power currently delivers about 17% of humanity’s electricity needs, and its role is likely to expand further in years to come as nations seek to reduce emissions of greenhouse gases and other airborne pollutants produced by fossil fuel production and consumption. The amount and rate of future growth in nuclear power production will depend in part on what advances the industry can make in the economics, safety, waste disposal, and proliferation resistance of current and future reactors. Certain classes of advanced fast-neutron reactors, and in particular novel designs known as traveling-wave reactors, offer potential improvements in many of these dimensions. In September 2002 the Generation IV International Forum selected six advanced, next-generation nuclear systems, three of which were fast-neutron reactors whose characteristics and benefits are well understood within the nuclear engineering community. Fast reactors use uranium much more efficiently than do thermal reactors such as light-water reactors (LWRs). Early design work and tests on fast reactors proved that they can operate as breeders. More recent—but as yet unproven—work has explored designs for fast reactors that consume minor actinides and some of the long-lived fission products in spent fuel removed from LWRs. One of the challenges of these well-known fast-reactor designs, both old and new, is that they rely on fuel reprocessing, which has ramifications for their economic feasibility and social acceptability. Recent design studies and physics calculations have demonstrated the feasibility of a newer variety of fast reactor called a traveling-wave reactor (TWR), also known as a breed-and-burn or a nuclear burning-wave reactor. Traveling-wave reactors would require no reprocessing. A TWR primarily uses depleted or natural uranium as fuel, with only a small amount of enriched uranium required at startup. For example, a 40-year TWR core would require roughly 3% of the amount of separative work units (SWUs) as an LWR of equivalent nameplate capacity would consume over 40 years, and the TWR would never need refueling. The longevity of a TWR core depends on the size of the initial charge of natural or depleted uranium and on the fuel burn-up achieved during reactor operation. We present our current designs for TWRs, which include both low power (100 MWe) and large (1,000 MWe) generation plants, with core configuration options that yield fuel burn-ups ranging from 20% to 50%. Specifics of these designs and the technical challenges that remain will be discussed.

FTA: "Enriching the uranium for reactor fuel and opening the reactor periodically to refuel it are among the most cumbersome and expensive steps in running a nuclear plant. And after spent fuel is removed from the reactor, reprocessing it to recover usable materials has the same drawbacks, plus two more: the risks of nuclear-weapons proliferation and environmental pollution.

These problems are mostly accepted as a given, but not by a group of researcher*s at Intellectual Ventures, an invention and investment company in Bellevue, WA. The scientists there have come up with a preliminary design for a reactor that requires only a small amount of enriched fuel--that is, the kind whose atoms can easily be split in a chain reaction. It's called a traveling*-wave reactor. And while government researchers intermittently bring out new reactor designs, the traveling-wave reactor is noteworthy for having come from something that barely exists in the nuclear industry: a privately funded research company."

The Traveling-Wave Reactor sounds incredible. Now they have to build a small prototype to convince people that it isn't science fiction. Someone once said that the more incredible the claim, the greater the burden of proof that is required.

The editors of Technology Review, MIT’s magazine of innovation, have announced their annual list of 10 emerging technologies with the potential to shape the way we live and do business. These revolutionary innovations—each represented by a researcher whose vision and work leads the field—promise fundamental shifts in areas from energy to health care, computing to communications. Technology Review’s editor in chief and publisher, Jason Pontin, will present the TR10 in India at the inaugural EmTech India conference, being hosted in conjunction with CyberMedia on March 2–3, 2009, in New Delhi.

The 2009 TR10 includes some technologies that should reach the market within a year, such as paper-based medical tests and virtual personal-assistant software. Others, like traveling-wave reactors and biological machines, could take a few years longer. The list includes technologies miniature and massive—from fast, cheap, capacious computer memory to batteries that can store enough energy to power a city.

Traveling-wave reactor. John Gilleland, manager of nuclear programs at Intellectual Ventures, is leading the development of a reactor that would run on depleted uranium, making nuclear power safer and less expensive.

Liquid battery. Donald Sadoway, a materials chemistry professor at MIT, has developed a liquid battery that could store enough electricity to allow cities to run on solar power at night.

Paper diagnostic test. George Whitesides, a professor at Harvard University, is using paper to create easy-to-use medical tests that could make it possible to quickly and cheaply diagnose a range of diseases in the developing world.

Biological machines. Michel Maharbiz, an assistant professor at the University of California, Berkeley, has developed a wirelessly controlled beetle that could one day be used for surveillance or search-and-rescue missions.

$100 genome. Han Cao, founder of BioNanomatrix, has designed a nanofluidic chip that could dramatically lower the cost of genome analysis. Combined with the right sequencing technology, Cao’s chip could allow doctors to tailor medical treatment to a patient’s unique genetic profile, map new genes linked to specific diseases, and quickly identify new viruses and outbreaks.

Racetrack memory. IBM fellow Stuart Parkin has created an entirely new type of data storage using magnetic nanowires. This “racetrack memory” could eventually replace all other forms of computer memory and lead to tiny, rugged, and inexpensive portable devices.

HashCache. Vivek Pai, a computer scientist at Princeton University, has created a new method for storing Web content that could make Internet access speedier and more affordable around the world.

Intelligent software assistant. Adam Cheyer, cofounder of the Silicon Valley startup Siri, is leading the design of powerful new software that acts as a personal aide. This virtual personal-assistant software helps users interact more effectively with Web services to complete tasks such as booking travel or finding entertainment.

Software-defined networking. Stanford computer scientist Nick McKeown developed a standard called OpenFlow that allows researchers to tap into Internet switches and routers to easily test new networking technologies with the click of a mouse—all without interrupting normal service.

Nanopiezotronics. Zhong Lin Wang, a materials scientist at Georgia Tech, is pioneering the field of nanopiezotronics. Wang is creating piezoelectric nanowires that generate electricity using tiny environmental vibrations; he believes they could power implantable medical devices and serve as tiny sensors.

A new way of fueling reactors could make nuclear power safer and less expensive as it needs only a small amount of uranium and doesn’t need to be opened from time to time.

A group of researchers at Intellectual Ventures, an invention and investment company in Bellevue, WA has come up with a preliminary design for a reactor called a traveling-wave reactor, which can generate power from uranium without damaging the environment and at a lower cost. This would reduce use of fossil fuels, reports the inaugural issue of the Indian edition of Technology Review, a 109-year magazine from Massachusetts Institute of Technology (MIT).

As it runs, the core in a traveling-wave reactor gradually converts nonfissile material into the fuel it needs. Nuclear reactors based on such designs theoretically could run for a couple of hundred years without refueling, says John Gilleland, manager of nuclear programs at Intellectual Ventures.

Enriching the uranium for reactor fuel and opening the reactor periodically to refuel it are among the most cumbersome and expensive steps in running a nuclear plant. And after spent fuel is removed from the reactor, reprocessing it to recover usable materials has the same drawbacks, plus two more: the risks of nuclear-weapons proliferation and environmental pollution.

Gilleland’s aim is to run a nuclear reactor on what is now waste. Conventional reactors use uranium-235, which splits easily to carry on a chain reaction but is scarce and expensive; it must be separated from the more common, nonfissile uranium-238 in special enrichment plants. Every 18 to 24 months, the reactor must be opened, hundreds of fuel bundles removed, hundreds added, and the remainder reshuffled to supply all the fissile uranium needed for the next run.

This raises proliferation concerns, since an enrichment plant designed to make low-enriched uranium for a power reactor differs trivially from one that makes highly enriched material or a bomb. But the traveling-wave reactor needs only a thin layer of enriched U-235. Most of the core is U-238, millions of pounds of which are stockpiled around the world as leftovers from natural uranium after the U-235 has been scavenged. The design provides “the simplest possible fuel cycle”, says Charles W. Forsberg, executive director of the Nuclear Fuel Cycle Project at MIT, “and it requires only one uranium enrichment plant per planet.”

The trick is that the reactor itself will convert the uranium-238 into a usable fuel, plutonium-239. Conventional reactors also produce P-239, but using it requires removing the spent fuel, chopping it up, and chemically extracting the plutonium—a dirty, expensive process that is also a major step toward building an atomic bomb. The traveling-wave reactor produces plutonium and uses it at once, eliminating the possibility of its being diverted for weapons.

Intellectual Ventures has patented the technology; the company says it is in licensing discussions with reactor manufacturers but won’t name them. Although there are still some basic design issues to be worked out—for instance, precise models of how the reactor would behave under accident conditions—Gilleland thinks a commercial unit could be running by the early 2020s.

When Microsoft Chairman and billionaire philanthropist Bill Gates mentioned TerraPower in his speech at the exclusive tech conference TED last week, it was the first time that many had heard of the nuclear project. I was monitoring Twitter during Gates’ talk and many audience members at TED tweeted wondering why “TerraPower” was getting special attention in a speech from one of the most famous computer technologists of all time.

Well, first off TerraPower is a nuclear spinoff project from incubator Intellectual Ventures. Former Microsoft chief technology officer Nathan Myhrvold founded Intellectual Ventures, and Bill Gates is a principal owner of TerraPower. TerraPower uses a “traveling wave reactor design,” which is technology that has been researched since the 1990’s, but according to MIT Tech Review TerraPower is the first company to “develop a practical design,” for travelling wave nuclear reactors.

There’s been a lot written about TerraPower over the past few years, and the company has done a good job of explaining how travelling wave reactors work in these videos on its incubator website. TerraPower’s President John Gilleland explains the process in one video as a new type of nuclear reactor that can provide an infinite amount of power, and unlike the current reactor design that uses only enriched uranium for fuel, TerraPower’s reactor largely uses waste byproduct of that enrichment process, or waste uranium.

TerraPower uses a small amount of enriched uranium at the beginning of the process (see slides at the bottom of the post), but then the nuclear reactor runs on the waste product and can make and consume its own fuel. The benefits are that the reactor doesn’t have to be refueled or have its waste removed until the end of life of the reactor (theoretically a couple hundred years). Using waste uranium reduces the amount of waste in the overall nuclear life cycle, and extends the available supply of the world’s uranium for nuclear by many times.

Not surprisingly, with its Microsoft connection, TerraPower has leaned heavily on supercomputing to design and model the reactor and the lifecycle of the fuel. The TerraPower team is using “1,024 Xeon core processors assembled on 128 blade servers,” which is a cluster that is “over 1000 times the computational ability as a desktop computer.” On Intellectual Venture’s site, they explain the importance of computer modelling as:
Extensive computer simulations and engineering studies produced new evidence that a wave of fission moving slowly through a fuel core could generate a billion watts of electricity continuously for well over 50 to 100 years without enrichment or reprocessing. The hi-fidelity results made possible by advanced computational abilities of modern supercomputer clusters are the driving force behind one of the most active nuclear reactor design teams in the country.

How close to reality is this technology? According to this presentation by Gilleland, “operation of a traveling wave reactor can be demonstrated in less than ten years, and commercial deployment can begin in less than fifteen years.”

TOKYO (AFP) – A company backed by Microsoft founder Bill Gates and Toshiba are in early talks to jointly develop a small nuclear reactor, the Japanese electronics giant said Tuesday.

The Nikkei business daily earlier reported that the two sides would team up to develop a compact next-generation reactor that can operate for up to 100 years without refueling to provide emission-free energy.

The daily said the joint development would focus on the Traveling-Wave Reactor (TWR), which consumes depleted uranium as fuel. Current light-water reactors require refueling every few years.

"Toshiba has entered into preliminary talks with TerraPower," said Toshiba spokesman Keisuke Ohmori. "We are looking into the possibility of working together."

Gates is the principal owner of TerraPower, an expert team based in the US state of Washington that is investigating ways to improve emission-free energy supplies using small nuclear reactors.

Unlike the current reactors at mega power plants, the smaller types could be introduced by cities or states or in developing countries more easily.

Ohmori said Gates, together with other TerraPower executives, had visited a Toshiba laboratory for nuclear power research near Tokyo last year.

"TerraPower is developing a small nuclear reactor and Toshiba is developing a different kind of small reactor. They were interested in Toshiba's technology and aiming at practical realisation" of small reactors, he said.

Ohmori said the two sides had just begun to "exchange information" but stressed that "nothing concrete has been decided on development or investment."

Gates is expected to use his personal wealth to back the development of TWRs and his investment could reach several billion dollars, the Nikkei said.

The news boosted Toshiba's share price by around four percent Tuesday.

The Nikkei said TerraPower had decided to join hands with Toshiba as it lacks the know-how to manufacture nuclear power equipment.

Toshiba, which owns US nuclear plant maker Westinghouse, has developed a design for an ultracompact reactor that can operate continuously for 30 years.

The company is preparing to apply for US approval to start constructing the first such reactor as early as 2014 and put it into practical use by the end of the decade, Ohmori said.

The WSJ has a new article about TerraPower, a start-up that plans to expand nuclear energy with a new reactor design. They claim their traveling wave reactor (TWR) could run for up to 100 years without needing to be refueled, making it safer and more efficient than conventional reactors.

The secret to the TWR's endurance is in the core. Conventional reactors sustain nuclear fission more or less uniformly throughout the entire fuel supply. In a TWR's core, only a small region of the fuel is undergoing fission at any given time. Because this limits the core's rate of fission, much more fuel can be built into the core without increasing the power output of the reactor. If conventional reactors are sprinters, then TWRs are marathon runners.

TerraPower hopes that the relatively maintenance-free TWR will gain a foothold in developing nations, where technical knowledge and specialized equipment are in short supply. The article points out that prospects for TWRs in the United States are bleak. Despite their advantages, regulatory restrictions make licensing any new reactor design in the US a very lengthy task.

Unfortunately, no amount of clever engineering can help to improve the public perception of nuclear power. In my experience, there are many people who dismiss nuclear power out of hand, without even trying to balance risks and benefits. Even a perfectly safe, perfectly efficient reactor will do nothing to change the minds of some folk.

Maybe a name change is in order. Magnetic resonance imaging (MRI) used to be called nuclear magnetic resonance (NMR). The name was changed for clinical applications to soothe patient fears over harmful radiation. Current generation nuclear power plants are so much safer than older style plants (like Chernobyl) that it seems a shame for them to share the same name.

A recent design for a nuclear reactor known as a traveling wave reactor looks similar to some conventional nuclear designs, but the way it operates is very different. Credit: Terrapower

Technology Review - Terrapower, a startup funded in part by Nathan Myhrvold and Bill Gates, is moving closer to building a new type of nuclear reactor called a traveling wave reactor that runs on an abundant form of uranium. The Terrapower reactor would burn up all of the actinides (uranium, plutonium). Most of the uranium that it uses would not need to be enriched.

The company has changed its original design to make the reactor look more like a conventional one. The changes would make the reactor easier to engineer and build. The company has also calculated precise dimensions and performance parameters for the reactor. Terrapower expects to begin construction of a 100-megawatt demonstration plant in 2016 and start it up in 2020. It's working with a consortium of national labs, universities, and corporations to overcome the primary technical challenge of the new reactor: developing new materials that can withstand use in the reactor core for decades at a time. It has yet to secure a site for an experimental plantâ€”or the funding to build it.

In the new design, the heat is always generated in about the same area within the reactor coreâ€”near the center. As a result, it's easier to engineer the systems to extract and use the heat to generate electricity.

One challenge with this design is ensuring that the steel cladding that contains the fuel in the fuel rods can survive exposure to decades of radiation. Current materials aren't good enough: for one thing, they start to swell, which would close off the spaces between the fuel rods through which coolant is supposed to flow. To last 40 years, the materials would need to be made two to three times more durable, Terrapower says.

Terrapower's next steps include finalizing the design and finding partners to build the plants. It's been in talks with organizations in China, Russia, and India. Gilleland says the company expects to have an announcement about partners within the next few months

In the original Terrapower design, the reactor core was filled with a large collection of uranium 238. The process of converting it starts at one end, producing plutonium that's immediately split to generate heat and convert more uranium to plutonium. The reaction moves from one end to the otherâ€”in a "traveling wave"â€”until no more reactions can occur.

In the new design, the reactions all take place near the reactor's center instead of starting at one end and moving to the other. To start, uranium 235 fuel rods are arranged in the center of the reactor. Surrounding these rods are ones made up of uranium 238. As the nuclear reactions proceed, the uranium 238 rods closest to the core are the first to be converted into plutonium, which is then used up in fission reactions that produce yet more plutonium in nearby fuel rods. As the innermost fuel rods are used up, they're taken out of the center using a remote-controlled mechanical device and moved to the periphery of the reactor. The remaining uranium 238 rodsâ€”including those that were close enough to the center that some of the uranium has been converted to plutoniumâ€”are then shuffled toward the center to take the place of the spent fuel.

Unites States is the leading producer and supplier of nuclear power in the world. 65 nuclear power plants use 104 commercial nuclear reactors to produce 799 billion kWhr of electricity in United States. The country produces almost 30% of the whole worldâ€™s nuclear power. New licenses have been given to increase nuclear power production by construction of another 24 new reactors. Following the disaster that struck Japan in the form or earthquake and tsunami, which resulted in massive damage to the nuclear reactors, extra safety measures are being provided to all the nuclear facilities in America.

The nuclear reactors used in America

Out of the 104 nuclear reactors in the US, 69 are pressurized water reactors and the rest are boiling water reactors. Travelling wave reactor was developed in the 1950s. However, nuclear power plants running on this technology are yet to be constructed. The main advantage of this technology is that it makes use of depleted uranium, which is the waste product of nuclear reactors and as of now, complete trash.

The principle of travelling wave reactor

The travelling wave reactors work on the principle of â€œonce-through cycleâ€. The reactor is designed such that the fissile material that is fed into it will be converted to nuclear fuel as per the requirements of the reactor. The big advantage of this reactor is that the nuclear feed or enriched uranium is required only to trigger the wave off in the reactor. Once the wave begins its onward move, it does not need to be supplied with further enriched uranium. As long as the depleted uranium is being supplied, the reactor continues to run. Therefore, the reactor saves a lot of fuel and money. Further, it is considered safer and more stable that the reactors that are in vogue today.

The necessity of travelling wave reactor

In the travelling wave reactor or TWR, the feed is depleted uranium. The major problem that nuclear reactors are facing is disposal of depleted uranium. The magnanimity of the problem is enhanced by the fact that the quantity of the waste multiplies every day. Therefore, unless there is an alternative that can utilize this radioactive material, disposal will become a huge problem. TWR not only uses the waste to generate power, the waste generated from it is very less, thus making it doubly advantageous. The dumping yards of depleted uranium can be considerably cleared if TWR is used.

The quantity of nuclear waste present in the United States

As of now, there are 38,000 canisters, each canister containing 14MT of uranium hexafluoride, lying in the dumping yard of Paducah. By using this waste as a fuel for TWR, a staggering 2,280,000,000,000 Megawatt hour of electricity can be produced. In all, the estimated amount of nuclear waste present in the United States is 700,000 metric tons. The amount present is so huge that 2.5 million homes in America can be supplied with electricity for one year, without the need of any other power generation source.

Thorium reactors are gonna beat the shit out of TWR's. Unit cost of energy generated, Inherent Safety due to non-fissile fuel, Fuel availability and from what I can gather almost twice the initial build cost when compared to an AHWR design and if claims are right the same when compared to a LFTR design.